There is considerable evidence that treatment for alcohol disorders can lead to significant improvements in substance use and psychosocial problem severity. However, a significant percentage of patients relapse to heavy drinking after primary treatment has ended. Patients are therefore frequently referred to aftercare programs in an effort to prevent relapse and the decrease the probability of additional rehabilitation treatments. Given the enormous social costs of alcoholism and the comparatively small resources for treatment, the appropriate use of aftercare could potentially have a large economic impact. However, there have only been a few studies of aftercare for alcoholics. In particular, there is very little empirical information on the efficacy of aftercare compared to minimal or no aftercare. Furthermore, there have been no studies of the cost-effectiveness of aftercare for alcoholics. We propose to evaluate the efficacy and cost-effectiveness of three approaches to aftercare for alcohol patients. Alcohol dependent patients who complete day hospital rehabilitation will be randomly assigned to one of the following interventions: (l) Minimal aftercare (MIN), a combination of referral to self-help groups and brief telephone case-management; (2) Standard disease-model aftercare counseling (STND), provided through two group therapy sessions per week; and (3) Individualized aftercare ('ND), provided through one individual cognitive- behavioral, relapse prevention session and one group therapy session per week. Each aftercare intervention will be l2 weeks in duration. Patients will be followed up at 3, 6, 9, l2, l8, and 24 months post intake into aftercare. Follow-up assessments will include measures of drinking and drug use (self-report, collateral reports, urine, and blood), psychosocial problem severity, and utilization of health and social services. Overall, individualized aftercare (IND) is expected to produce the best outcomes, followed by standard aftercare (STND), and minimal aftercare (MIN). Analyses will also be done to test four patient-treatment matching hypotheses. Lower psychiatric severity and better social support will predict relatively good outcomes in MIN aftercare, compared to STND and IND; whereas more problematic scores on these measures will predict differentially better outcomes in IND. Low sociopathy and poor neuropsychological functioning will predict better outcomes in STND than in IND, whereas high sociopathy and better neuropsychological functioning will predict better outcomes in IND. For the cost-effectiveness component of the project, we will assess aftercare costs, other health costs (e.g., additional inpatient and outpatient treatment), and other economic costs (e.g., crime, accidents, productivity). These data will be used to perform a comprehensive analysis of the cost-effectiveness of aftercare for alcohol patients. Furthermore, the cost-effectiveness of different approaches to aftercare for specific subgroups of patients will be determined. Overall, the STND condition is expected to be the most cost-effective form of aftercare. However, it is expected that MIN aftercare will be cost-effective for low -problem severity ("good prognosis") patients, whereas IND aftercare will be cost- effective for high problem severity ("poor prognosis") patients.